Apparatus for treatment of turbid liquids



2 sheets-sheet 1 R. R. KENNEDY APPARATUS FOR TREATMENT OF TURBID LIQUIDS INVENTOR. @fC- hard R, /l/e/fneo/y BY @j Q' l ATTORNEY Aug., s, 195o Filed Sept. 7, 1946 Aug. 8, 1950 R. R. KENNEDY APPARATUS FoR TREATMENT oF TURBTD LIQuTns 2 Sheets-Sheet 2 Filed Sept. 7, 1946 NVENTOR. /'caro/ l?. Kennedy ATTORNE Patented Aug. 8, 1950 APPARATUS Fon' TREATMENT 0F TURBID l LIQUIDs Richardl aKen'neay, Palo Alto, Calif.

Application September 7, 1946, Serial No. 695,521

6 Claims.

This invention relates to the treatment of turbid liquids as may be provided by water, sewage, tradewastes, chemicals and, in` fact, any liquid from which it is desired to remove solids.

More particularly, the present invention relates to an improved apparatus for the purification of liquids.V This apparatus comprises a generally rectangular tank or trough through which the liquid'to be purified flows from o ne end to the other. At the inlet end of the tank means are providedfor releasing air in the influent liquid to aerate the liquid, to sweep out of the liquid any entrained gases, to satisfy the biological oxygen demand of the liquid yand to coagment solids in the liquid and to keep solids in a mobilized suspension by the air agitation until the solids have collected into settleable ocs. Preferably the tank or trough is so arranged that aeration is effected only in the initial portion of the tank, the remainder of the tank being available for sedimentation. In accordance with this invention, the sedimentation zone is, in fact, provided by two different regions in the tank, one region being immediately adjacent tothe aeration zone vwhile theother is provided by the remainder of the tank; the two sedimentation regions are separated by a dividingor partitioning means which extends transversely 'of the tank or trough `and substantially delneates one region from the other so that only a regulated liquid transfer occurs. Insofar as the individually desired operating devices are concerned, this dividing or partitioning means can take vthe form of a baille Wall structure extending transversely of the tank and so positioned that the liquid can .flow through the tank freely andfvwithout such restriction'as resultsv in the breaking up of the fiiocs present in the water.4

. In prior apparatus1 ofthe same'general type and in which a liquid is arranged to flow generally in a horizontal-direction through a channel in which initially iiocculation vis attempted, followed by a later sedimentation, dependence is placed upon theffluid currents yestablished in the liquid tolcarry'the flocs and move these on into `a sedimentation zone.v In zpractice, this has not proven satisfactory, particularly when the agitation is effected b'y'mechanical means, for-the tendency existsyf'for, vthe settleable iiocs to vbuild up into a pile or ypiles in those regionsof the 'tankA whereinthe agitationis at a minimum. Obviously, if .the agitation, is suiiiciently. vigorous to ensure that lall of the settleable flocs which Tay form arggovedzlgvsr intothe vS,@dimmi@imn zone, then the agitation is so vigorous that the flocs, if formed, are broken with the result that vthereafter the flocs are only re-formed with difiiculty into those of a settleable size. As a consequence, the agitators are operated at a relatively slow or reduced speed so that inefficient coagmentation occurs andthe settleable ocs form piles of sludge in or adjacent to the flocculation zone, Depending upon the quantity of the sludge and the nature `ofthe sludge, variious difficulties may result from its building up into a. pile or piles in the tank; it will be obvious in the case of sewage that such a pile would become septic as a result of too long retention or stagnation.

In accordance with this invention, air agitation rather than mechanical agitation is employed, because of the desirable advantages of sweeping out of the liquids any entrained gases, because the flocs can be coagmented as successfully with air as by mechanical means, becauseA any biological demand of the liquid can be satised by the aeration, because grease, usually present in sewage, is easily swept out of the water and collected and for other presently detailed reasons.

By effecting ilocculation, coagmentation and partial sedimentation on one side of the baiile Wall, the other sedimentation region can be utilized to effect a more complete clarification of the effluent liquid. With the liquid circulation between the two sedimentation regions of onlyr limited extent, the sedimentation in each region proceeds under more or less localized conditions; in that region in intimate contact with the aeration-occulation zone, coagmentation proceeds fairly rapidly and a large portion of the total solids removal is effected in this region; the eiiluent, partially clarified liquid, passing the baffle to the second sedimentation zone, vmoves very slowly past the baffle, carrying a relatively low solid Icontent per unit of liquid volume; the effluent liquid removed from `adjacent the upper level of-y the liquid so that the solids are afforded ample opportunity to coagment and settle in the second region without disturbance from the agitation of the aerating stream in the flocculation-coagmentation zone.

In addition to the advantages recited, 'the present invention also contemplates the utilization of a rake or conveyor structure for removing yall of the solids which settle to the bottom of the tank into a sludge collection pocket'for eventual removal. In accordance with this invention, the `settled solids are swept along the tank bottom from the influent end of the tank to the eiiluent end, this type of removal of the solids possessing the inherent advantage that thereby the liquid and the separated, settled solids move in the same direction so that the flow of liquid does not tend to break up and destroy the settled flocs as is the case when the settled solids are moved countercurrent to the flow of liquid.

One object of the present invention is to profvide an improved process and apparatus for the clarication of turbid liquids and the removal of solids from such liquids.

Another object of the present invention is to provide for the continuous removal of settled solids without interference with the operation of the equipment or the flow of uid.

A further object of the present invention is to improve the over-all eiciency of a combined flocculation-sedimentation unit.

The invention includes other objects Aand features of advantage, some of which, together with thevforegoing, will'be' set forth in the following description.

In the drawings accompanying and-forming a part hereof, I have illustrated the bestembodiment of invention now known to me but such embodiment is to be regarded as typical only of many possible embodiments and the invention is not limited thereto.

In the'drawings accompanying and forming a part hereoLFigure 1 is a plan view of the flocculatlng sedimentation unit of the present invention.

Figure 2 is a section taken along the 'line 2-2 of Figure 1.

Figure 3 is a section taken along the line 3--3 in Figure 1.

Figure 4 is a section taken along the line 4 4 in Figure 1.

In the drawings, and referring particularly to Figure l, I have shown a plurality of units I l in a side by side relation, each unit substantially comprising a tank or horizontal vessel 'through which liquid is adapted to flow from one end of the tank to the other. Each unit l l comprises a bottom l2, suitable vertical side walls 13,- end walls 14' and i5, and operator walk-ways 23 supported by columns 23. An inlet pipe i6 delivers the influent liquid to be treated to a common as Ylaunder l 'i having a wall i 8 over which the liquid ows into each unit; to ensure uniform liquid release into the end units, a bale 253 is positioned in the launder to ensure uniform liquid release. vided a balfle wall i6 extending transversely of vthe tank and spaced from the Vbottom of the tank to permit the fluid to circulate past the baffle wall at a low velocity. 'The upper end of the baille wall is positioned below the elevation of launder wall i8 so that fluids can flow over the top-ofthe 'balile wall. Along the top of the b'ailie wall is provided a v'skimming pipe I9 so that solids floating `on the top of the liquid in the tank can be removed.

'The baffle wall serves to divide the tanks into ya rstfsec'tio-n 2l and a second section 22. In the first section of the tank, air is released'from a plurality of air diff-users generally indicated by numeral I23. 'In 'accordance-With this invention, the air 'diffusers are positioned immediately adjacent to the wall 1'4 at the inlet 'end of the tank "so that the aeration'of the liquid and any circulation `lof fluid due to the `release Uof air takes 'place 'in 'this portion of the tank, the release of Intermediate walls VHl andl i5 is proair being effective to sweep out any entrained gases, to coagment floc present in the fluid, and to sweep out of the water grease and the like to the tcp of the water or liquid for removal by the skimming pipe I9. It will be noted that the air diffusers 23 stop short of the balile wall I8 so that flocculation and sedimentation can occur in tank portion 2l and so that baffle i3, in effect, divides the tank into two immediately adjacent sedimentation zones.

In the second tank section 22, means are provided for withdrawing clarified liquid. This means comprises the launder 26 which is supported between the opposite side walls and by one or more columns 29 and which extends transversely of the tank and leads to an effluent oonduit (not shown). Liquid is admitted to the launder 23 by a plurality of feed troughs 21 eX- tending on each side of launder 2G along the run of the tank and supported between trough 26 and operator walkways 2B. The horizontally extending troughs 2 are relatively shallow in depth to ensure that the liquid entering into the effluent launder E@ is moving at a very slow rate so that any solids in the liquid in a lower portion `oi the tank are not disturbed.

Top-rovide lfor removal of settled solids, in ac-r cordance with this invention, a movable rake or sludge conveyor is provided for moving the settled solids along the tank bottom. This comprises a rst shaft 3| provided at the inlet end of the tank, a second shaft 32 provided at the other end of the tank adjacent to sludge sump 33 and a third shaft 34 provided adjacent wall i5 but toward the top of the tank between shafts 3l and 32. Suitable sprocketsvSt are provided on each shaft on opposite sides of the tank; labout these are trained suitable conveyor chains 31 carrying a plurality of spaced rake arms 38. 'Shaft 3d is driven by suitable means (not shown) to `move the conveyor'cliains so that the several rake arms 38 move'across `the bottom of the tank slowly to sweep solids on toward the sludge sump 33 in the direction of movement of the liquid,

Sludge delivered 'to the sump 33 is moved into a'pocket 4l by the mechanism shown particularly in Figures 2 and 4 and which comprises a shaft 42 supported upon a column 43 and having a sprocket 44 provided adjacent each end. Shaft 42 is driven by a suitable prime mover (not shown) rotating shaft 4B, a chain 4l being trained about a sprocket 48 on shaft 46 and about a sprocket 129 on shaft '152. Shaft 5| is provided at one end of sump33 and shaft 52 at the other end of the sump and adjacent the pocket 4I. Sprockets 53 are provided on Ythese and chains'54 are trained about the several sprockets. Upon rotation of shaft 42, conveyor chains 54 are `moved to carry arms 55 over the bottom of the sludge'pocket 33 and to sweep any sludge therein on into the sludge pocket 4I from which it can be suitably removed.

In operation, with the unit I I lled with liquid 'to the level indicated and with air released at av vsuitable rate through the air diffuser 23, the liquid is swept free of entrained gases while grease and the like is swept to the top of the liquid for removal by the skimmingrpipe 119. In addition, any flocs present in the liquid Aare coagmented and caused to form into larger masses which settle, generally between b afe wall I6 and the air diffusers. The substantially clarified liquid flows over or under the bale vI3 into the larger sedimentation zone 42 whereinfurther opportunity for sedimentation is afforded under nearly absolutely quiescent vconditions 'andfree `of the disturbing influence oi the ilocculator-aerator. The finally claried liquid is removed as it passes over the trough 27 to issue into the launder 2B. In this way, the liquid is treated to remove the solids causing turbidity, all portions of the tank being swept by the conveyor structures so that the formation of septic masses is entirely obviated. l

I claim:

l. Apparatus for the clarification of turbid liquids having solids therein, consisting of a tank having a bottom, two parallel side walls, land inlet and outlet ends, a turbid liquid inlet atk the inlet end, a clarified liquid outlet at an upper portion of the outlet end, a solids outlet at a lower portion of the outlet end of the tank, a baille between said side walls and having its lower horizontal edge spaced from the bottom of the tank and its upper horizontal edge adjacent the level of the liquid outlet and spaced from the inlet end and the outlet end to divide the tank into (a) an agitation and rst sedimentation zone and (b) a second sedimentation zone, means for agitating liquid and solids in the tank in' a zone immediately adjacent to the inlet end and spaced from the baille to provide said first sedimentation zone between the baille and the agitating means, conveyor means for sweeping solids along the bottorn and means for moving said conveyor means to move solids on the bottom from the inlet end through both zones to the outlet end.

2. Apparatus for the clarification of turbid liquids having solids therein, consisting of a tank having a bottom, two walls, and inlet and outlet ends, a turbid liquid inlet at the inlet end, a solids outlet at a lower portion of the outlet end of the tank, a substantially vertical baille extending from wall to wall and having its lower horizontal edge spaced from the bottom and its upper horizontal edge positioned adjacent the level of the liquid outlet and dividing the tank into (a) an agitation and rst sedimentation zone and (b) a second sedimentation zone, means for in" troducing air to agitate liquid and solids in the tank in a zone immediately adjacent to the inlet end and spaced from the baille to provide said first sedimentation zone between the baille and the agitatng means, a conveyor having operative and return reaches both passing between the lower horizontal edge of the baille and the tank bottom and means for moving said conveyor to sweep solids along the bottom from the inlet end through both zones to the outlet end.

3. In apparatus for clarifying liquid including an elongated tank containing a pool of the liquid and in which the liquid flows lengthwise from an inlet end to an outlet end, the combination which comprises an air disperser mounted below the pool level in the inlet end, a baille disposed across the tank at a substantial distance from the air disperser with a substantial open space in the tank underneath the baille to permit flow of the liquid and with the top of the baille approximately at the pool level, there being relatively quiescent zones in the pool adjacent both sides of the baille, a conveyor for scraping settled solids along the bottom of the tank in the direction of the liquid flow therein and underlying the zone in which the air disperser is disposed and the two quiescent zones, the space between the conveyor and all three zones being substantially unobstructed so that settlement of solids to the bottom can occur inall three zones, and means for removing claried liquid from the pool in the quiescent zone beyond the baille. n

4. Apparatus according to claim 3 provided with means for removing scum from the pool adjacent the top of the baille.

5. Apparatus according to claim 3 provided with a second conveyor disposed in the tank transversely to the first adjacent the bottom' in the quiescent zone beyond the second baille for moving solids carried by the first conveyor across the tank bottom, and a sludge .pit in the bottom into which the solids are moved by the second conveyor.

6. Apparatus according to claim 3 in which the means for removing clarified liquid from the pool in the quiescent zone beyond the baille comprises a main launder running across the tank at approximately the level of the pool, and a plurality of collection launders discharging into the main launder and running lengthwise of the tank at approximately the level of the pool.

RICHARD R. KENNEDY.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 599,957 Curtis Mar. 1, 1898 1,714,739 Tark May 28, 1929 1,981,310 Currie Nov. 20, 1934 2,087,851 Darby July 20, 1937 2,110,721 Fischer Mar. 8, 1938 2,215,185 Lund Sept. 17, 1940 2,272,441 Streander Feb. 10, 1942 2,322,017 Hartman June 15, 1943 2,370,974 Langdon Mar. 6, 1945 FOREIGN PATENTS Number Country Date 27,240 Great Britain 1905 

